/* Copyright 2024 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#ifndef TENSORFLOW_CORE_COMMON_RUNTIME_COLOCATE_PREDECESSOR_TREES_PASS_H_
#define TENSORFLOW_CORE_COMMON_RUNTIME_COLOCATE_PREDECESSOR_TREES_PASS_H_

#include "tensorflow/core/common_runtime/optimization_registry.h"

// Colocate a tree of unplaced constants with its placed root. Identify a
// dangling tree of ops whose root op is assigned but rest of ops are not
// assigned. Then it should colocate the rest of the ops with the root op.
//
// For example, the graph before pass is:
//
//   node {
//     name: "const0"
//     op: "Const"
//   }
//   node {
//     name: "const1"
//     op: "Const"
//   }
//   node {
//     name: "fill0"
//     op: "Fill"
//     input: "const1"
//     input: "const0"
//   }
//   node {
//     name: "id0"
//     op: "Identity"
//     input: "fill0"
//     device: "/job:worker/replica:0/task:2/device:CPU:0"
//   }
//
// The graph after pass is:
//
//   node {
//     name: "const0"
//     op: "Const"
//     attr {
//       key: "_class"
//       value {
//         list {
//           s: "loc:@id0"
//         }
//       }
//     }
//   }
//   node {
//     name: "const1"
//     op: "Const"
//     attr {
//       key: "_class"
//       value {
//         list {
//           s: "loc:@id0"
//         }
//       }
//     }
//   }
//   node {
//     name: "fill0"
//     op: "Fill"
//     input: "const1"
//     input: "const0"
//     attr {
//       key: "_class"
//       value {
//         list {
//           s: "loc:@id0"
//         }
//       }
//     }
//   }
//   node {
//     name: "id0"
//     op: "Identity"
//     input: "fill0"
//     device: "/job:worker/replica:0/task:2/device:CPU:0"
//     attr {
//       key: "_class"
//       value {
//         list {
//           s: "loc:@id0"
//         }
//       }
//     }
//   }

namespace tensorflow {

class ColocatePredecessorTreesPass : public GraphOptimizationPass {
 public:
  Status Run(const GraphOptimizationPassOptions& options) override;
};

}  // namespace tensorflow

#endif  // TENSORFLOW_CORE_COMMON_RUNTIME_COLOCATE_PREDECESSOR_TREES_PASS_H_
